Connecting and disconnecting offshore structures, such as wind turbines, frequently requires the use of a crane barge. Embodiments described below allow these structures to be assembled offshore without a crane barge. Embodiments disclosed may assist with assembly or serve as a mating device. The ability to install and/or uninstall wind turbines to a floating platform, such as a spar buoy, without a crane barge may save significant amounts of time and money for the operator.